Apparatus for joining together the opposite ends of a belt-shaped member

ABSTRACT

A belt-shaped member cut into a predetermined length is fed from a feeding devices to a tire forming drum and is wound on its cylindrical peripheral surface. Center portions of the opposite ends of the belt-shaped member are pushed to be joined to each other and the side portions of at least one of the opposite ends of the belt-shaped member are held by upper and lower holding pawls. Such holding pawls are swung along an arcuate path so that both side portions of the opposite ends of the belt-shaped member are drawn near each other to abut against each other. The abutting end portions are pushed toward the peripheral surface of the drum by pushing devices for joining them together.

This is a continuation-in-part of application Ser. No. 08/432,941, filedMay 1, 1995 now abandoned.

FIELD OF THE INVENTION AND RELATED ART STATEMENT

The present invention relates to a method and apparatus for joiningtogether the opposite ends of a belt-shaped member. More specifically,the present invention relates to a method and apparatus for feeding along, narrow member or belt-shaped member cut into a predeterminedlength, such as a tread, to a tire forming drum to wind the belt-shapedmember on a cylindrical peripheral surface of the drum and joiningtogether both opposite ends of the belt-shaped member.

The belt-shaped member therein considered is more particularly anon-vulcanized rubber constituent member of a raw tire, or morespecifically a tire tread, the cross section of which is substantiallytrapezoidal-shaped and has a thick center portion provided with taperedside portions which outwardly end with thin side edges. Accordingly,when the belt-shaped member is cut into a predetermined length, both theside portions thereof shrink so that its cut end sections, the so-calledstarting and terminating ends, are curved.

Such a belt-shaped member is usually wound on the cylindrical peripheralsurface of a tire forming drum by using a tire forming machine andperforming a known belt-shaped member affixing method (for example ofthe type disclosed in U.S. Pat. No. 5,292,398).

However, when the center portion of the starting end and the centerportion of the terminating end of the belt-shaped member are positionedin opposed orientation to be joined to each other, substantiallyV-shaped gaps form at both side portions of the belt-shaped member dueto the aforesaid shrinkage of the side portions thereof.

In particular, in the case of the known belt-shaped member affixingmethod, an actual length of the belt-shaped member T (see annexed FIG.5) is measured before affixing of the member T. The starting end of thebelt-shaped member T is then adhered at a predetermined position of thetire forming drum and the terminating end of the belt-shaped member isfixed on a conveyor by a clamp manipulator. The peripheral speed of thetire forming drum and the moving speed of the conveyor are then adjustedto wind the belt-shaped member T on the peripheral surface of the tireforming drum while extending the belt-shaped member T to a requiredlength, so that the center portion of its starting end and the centerportion of its terminating end are positioned in opposed orientation tobe joined together at point E of FIG. 5. According to this method, whenthe center portions of the starting and terminating ends are joined toeach other, V-shaped gaps form at both side portions of the ends of thebelt-shaped member T. The top and bottom side extensions of suchV-shaped gaps are respectively indicated X1 and X2 in FIG. 5.

Accordingly, in the aforesaid belt-shaped member affixing method usingthe above tire forming machine, it is necessary to join by hand both theside portions (shrinkage portions) of the starting and terminating endsof the belt-shaped member while extending the belt-shaped member by thelength of the shrinkage portions.

As a countermeasure for solving such a drawback, end portion joiningmethods for belt-shaped members have been proposed, for example by U.S.Pat. No. 4,804,426 or JP 3-190,725, in which holding pawls are used tohold both side portions of at least one of the starting end or theterminating end, such holding pawls being moved along the peripheralsurface of the tire forming drum to relatively draw the side endportions of the starting end with respect to the side end portions ofthe terminating end in order to approach them so that the starting andthe terminating ends of the belt-shaped member are positioned in opposedorientation to be joined to each other.

However, in the belt-shaped member end joining method according to theprior art, in consequence of the fact that the holding pawls are movedalong the peripheral surface of the tire forming drum along a directionparallel to the belt-shaped member, the following problems arise.

If the width of the belt-shaped member to be held is wide, it does notsucceed in exactly joining together the side portions of the startingand terminating ends. This is because of the reciprocal abutment of thecenter portions of the ends of the belt-shaped member, which impedesboth side ends of the starting and terminating ends of the belt-shapedmember from being joined together.

If the width of the belt-shaped member to be held is instead narrow,only the portions actually held by the holding pawls are extended, withthe unheld portions in the vicinity of the held portions not beingbrought into engaging proximity. Thus, the starting and terminating endsof the belt-shaped member can not be joined exactly.

More specifically, the methods and apparatuses known from the prior artteach to use holding pawls which can be moved only along the cylindricalperipheral surface of the forming drum, that is only along thelengthwise direction of the belt-shaped member wound on it. Due to thisfact, the reciprocal abutment of the central portions of the startingand terminating end sections of the belt-shaped member hinder thebringing into contact of the corresponding side portions of the startingand terminating ends. Thereby, the side V-shaped gaps which form betweenthe starting and terminating ends can not be eliminated.

SUMMARY OF THE INVENTION

The present invention has been made in order to overcome the aboveproblems, and provides a method and an apparatus allowing automatic andexact joining together of the opposite ends of a belt-shaped member,such as a tread.

The method according to the present invention is for joining togetherthe opposite ends of a belt-shaped member. Each of the ends comprises acenter portion interposed between two thinner side portions. The methodincludes the steps of feeding said belt-shaped member cut into apredetermined length from a feeding device to a tire forming drum havinga cylindrical peripheral surface; winding said belt-shaped member onsaid cylindrical peripheral surface of said tire forming drum; pushingboth end center portions of said opposite ends with respect to eachother to join them together, thereby forming a pair of oppositesubstantially V-shaped side gaps between the side portions of theopposite ends of the belt-shaped member, said V-shaped side gaps havinga respective vertex adjacent to the joined end center portions; holdingboth side portions of at least one of said opposite ends of thebelt-shaped member by respective holding devices arranged in proximityof the V-shaped side gaps; swinging said holding devices each along anarcuate path the center of which is located adjacent, e.g.,substantially in correspondence with, the vertex of the respectiveV-shaped gap, for bringing the side portions of both opposite ends ofsaid belt-shaped member together until they abut against each other.

In accordance with the invention, the starting and terminating endsections of the belt-shaped member are brought into contactsubstantially over their whole width, so as to eliminate even wideV-shaped gaps formed between the side ends of the opposite ends of thebelt-shaped member, notwithstanding the reciprocal abutment of thecenter portions of the end sections of the member.

The present invention further provides an apparatus for joining bothends of a belt-shaped member wherein each end comprises a center portioninterposed between two thinner side portions, the belt-shaped memberbeing cut into a predetermined length and being fed from a feedingdevice to a tire forming drum which is rotatable about an axis and has aperipheral cylindrical surface, wherein the belt-shaped member is woundon said peripheral cylindrical surface and the center portions of itsopposite ends are joined, thereby forming a pair of opposite V-shapedside gaps between the side portions of the opposite ends of thebelt-shaped member, said V-shaped side gaps each having a respectivevertex adjacent to the joined end center portions. The apparatusaccording to the invention comprises a pair of moving rests adapted tobe moved along both a radial direction and an axial direction withrespect to said drum. Arms are connected to the moving rests. The armsare adapted to be swung about respective axes radially extending withrespect to the axis of said drum and passing through a point locatedadjacent, e.g., in substantial proximity of said vertex of the V-shapedgaps. Holding devices are connected to said arms for holding and drawingtogether side end portions of said belt-shaped member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view showing an example of an apparatus for joining theopposite ends of a belt-shaped member, for use in implementation of aboth ends joining method of the present invention;

FIG. 2 is a front view taken along line a--a of FIG. 1;

FIG. 3 is a bottom view taken along line b--b of Fig.2;

FIG. 4 is a side view taken along line c--c of FIG. 3; and

FIG. 5 is a schematic elevation view illustrating the ends of abelt-shaped member joined by a method according to the prior art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIGS. 1 to 4, an embodiment of a both ends joiningapparatus for use in implementation of a method of joining the ends of abelt-shaped member, according to the present invention, is described.

In FIG. 1, numeral 1 denotes a tire forming drum having a cylindricalperipheral surface. A support and drive device 2 of the tire formingdrum 1 is shown, as is a frame 3 for a device for feeding a belt-shapedmember T as a tire tread, and a conveyor 4 for conveying the device forfeeding the member T. Further, a centering device of the member T isprovided, this centering device being well known in the art andtherefore not shown.

Further, numeral 5 denotes a bracket of the both end section joiningapparatus, which is fixedly mounted to the support and drive device 2, amotor 8 mounted to the bracket 5 by means of bolts, and a verticallymoving base 7 which is slidably mounted to the bracket 5 along a radialdirection with respect to the tire forming drum 1 through a directlydriven bearing 6.

In FIG. 2, numeral 9 denotes a screw rod having an end fixedly mountedto the vertically moving base 7. A nut (not shown) engaged by the screwrod 9 is rotatably mounted to the bracket 5 and an endless belt ismounted between an output shaft of the motor 8 and said nut, so thatrotation of the motor 8 is transmitted through the endless belt to thenut to rotate it for vertically moving the screw rod 9 together with thebase 7.

Further, numeral 10 denotes a rail fixedly mounted to the verticallymoving base 7 and numeral 12 denotes one of a pair of moving restsslidably mounted along the rail 10 through directly driven bearings 11.The moving rests 12 can be moved parallel to the axis of the tireforming drum 1, along the rail 10.

Numeral 13 denotes a screw rod which is arranged parallel to the rail 10and has a left-handed screw portion and a right-handed screw portion.Both ends of the screw rod 13 are rotatably mounted to the verticallymoving base 7 and respective nuts are fixedly mounted to the movingrests 12 for the engagement by the screw rod 13.

Numeral 15 denotes a motor fixedly mounted to the vertically moving base7, which has an output shaft fixedly supporting a first pulley (notshown). An endless belt 14 is wound around the first pulley and alsoaround a second pulley (not shown) fixed to one end of the screw rod 13,so that rotation of the motor 15 is transmitted to the screw rod 13through the first pulley, the endless belt 14 and the second pulley. Therotation of the screw rod 13 causes the sliding movement of both movingrests 12 along the rail 10, so that they approach or move away withrespect to each other.

Numeral 17 denotes one of four L-shaped arms, a pair of L-shaped arms 17being provided at each side of the belt-shaped member T. Each arm 17 isswingably mounted on a respective pin 16 associated with a moving rest12 and arranged substantially in the radial direction with respect tothe axis of the forming drum 1. In particular, each of the arms 17 canswing about the respective pin 16 and therefore about an axissubstantially perpendicular to the peripheral surface of the formingdrum 1.

Further, each arm 17 is provided with a holding device adapted to clampa side end portion of the belt-shaped member T. In particular, as shownby FIG. 2, the holding device comprises for each arm 17 a lower holdingpawl 19 mounted at a lower end portion of the respective arm 17, forexample by means of screws. A pair of fluid pressure cylinders 18 (bestshown in FIG. 3) are mounted to each of the moving rests 12 throughrespective pins 18a, and each fluid pressure cylinders 18 is coupledwith one of the arms 17. A piston rod 30 extends from each cylinder 18and has a tip coupled with the respective arm 17 through a pin 31parallel to the pin 16 of the same arm 17. Each fluid pressure cylinder18 can be extended or retracted in order to swingably move therespective arm 17 about its pin 16.

The aforesaid holding device further comprises for each arm 17 an upperholding pawl 22 supported at an inner end portion of a movable lever 21.In particular, each lever 21 is swingably mounted at the center portionthereof to an arm 17 through a pin 32 transverse to the respective pin16, in order that its upper holding pawl 22 can be moved with respect tothe holding pawl 19 of the same arm 17. For this purpose, a fluidpressure cylinder 20 is mounted to each arm 17, each cylinder 20 havinga piston rod 33, a tip of which is coupled with the outer end portion ofthe respective lever 21 through a pin 34 parallel to the pin 32 of thatlever. By retracting or extending each fluid pressure cylinder 20, therespective lever 21 swings about the pin 32 so that the upper holdingpawl 22 approaches or moves away with respect to the corresponding lowerholding pawl 19.

In FIG. 4, numeral 26 denotes a pushing member or pusher associated to arespective moving rest and adapted for simultaneously pushing both sideportions of the starting and terminating ends of the member T which arelocated at a same side of the member T, when they abut with each other.Numeral 23 denotes a fluid pressure cylinder fixedly mounted to one ofthe moving rests 12, having a piston rod 35 at a tip of which therespective pusher 26 is mounted through a guide block 24 and a spacer25.

The operation of the both end joining apparatus for belt-shaped membershown in FIGS. 1 to 4 is described in detail in the following.

A belt B (shown in FIGS. 2 and 4) is usually affixed on the peripheralsurface of the tire forming drum 1. Then, a belt-shaped member T cutinto a predetermined length is fed to the drum 1 from the feedingdevices 3 and 4, and it is wound on the peripheral surface of the drum1, and therefore on the belt B, so that the center portions of thestarting end and of the terminating end of the belt-shaped member T arepushed and joined together by pushing means (not shown). As in therelated art shown in FIG. 5, a pair of opposite V-shaped side gaps areformed between the side portions of the opposite ends of the belt-shapedmember T, each V-shaped side gap having the vertex adjacent to thejoined end center portions.

Referring back to FIGS. 2 and 4, the motor 15 is then driven and therotation thereof is transmitted to the screw rod 13 through the firstpulley, the endless belt 14 and the second pulley to rotate the screwrod 13, so that the moving rests 12 are moved from their waitingpositions to the operative positions respectively approached to one ofthe side ends of the belt-shaped member T.

In the meanwhile, the fluid pressure cylinders 18 are operated forswinging the arms 17 about the respective pins 16 in order to open in acorresponding V-shaped configuration each pair of arms 17 associated toa same moving rest 12. In this way, the lower holding pawls 19 of thearms 17 are each inserted between a side portion of the belt-shapedmember T and the tire forming drum 1, in proximity of the starting andterminating ends of the member T and therefore adjacent to the edges ofthe V-shaped gaps.

The fluid pressure cylinders 20 are then operated to swing the levers 21so that their upper holding pawls 22 are moved down towards therespective lower holding pawls in order that both side portions of thestarting and terminating ends of the belt-shaped member T are eachclamped between an upper holding pawl 22 and a lower holding pawl 19.

Then, the fluid pressure cylinders 18 are operated in the oppositedirection, for swinging the arms 17 about the pins 16 in order to movethe arms 17 of each pair of arms associated to a same moving rest 12toward each other in a closing direction, so that both side portions ofthe starting end and the terminating end of the belt-shaped member T aredrawn near each other from their opened V-shaped configuration by thelower holding pawls 19 and the upper holding pawls 22, until their sideends abut against each other. In particular, under the operation offluid pressure cylinders 18, each pair of holding pawl 19 and 22 ismoved along an arcuate path P (shown in FIG. 3), the center of which islocated at pin 16 which is substantially in correspondence with alocation between the side portions of opposite ends of the belt-shapedmember, e.g., substantially in correspondence with the vertex of theadjacent V-shaped gap, so that the opposite edges of each V-shaped gapare moved toward each other until they abut.

The fluid pressure cylinder 23 is then operated to move down the pusher26 so that the side end portions of both starting and terminating endsof the belt-shaped member T are simultaneously pushed towards thesurface of the drum 1 to be joined against each other.

Afterward, the fluid pressure cylinder 23 is operated in the oppositedirection to raise the pusher 26, the upper holding pawls 22 are raisedwith respect to the lower holding pawls 19 for opening the holdingdevices, and the moving rests 12 are moved back to their waitingposition. Thus, the winding and joining processes of the ends of thebelt-shaped member T are completed.

In the foregoing description, the end side portions of the belt-shapedmember T are spaced to form V-shaped gaps which are held and drawntoward each other by two sets of holding devices, i.e., a set for eachof the opposite ends of the member T, each set comprising a pair oflower holding pawls 19 and corresponding upper holding pawls 22.However, a method according to the present invention can be alsoperformed by fixedly holding and drawing the side portions of only oneend of the member T with respect to the other end, and therefore byusing only one set of holding devices.

According to a method and apparatus for joining together the oppositeends of the belt-shaped member according to the invention, thebelt-shaped member cut into a predetermined length is fed from thefeeding device to the tire forming drum to be wound on the peripheralsurface of the drum and the center portions of the starting andterminating ends of the belt-shaped member are pushed and joinedtogether. Then, both end side portions of at least one of the startingand terminating ends of the belt-shaped member are held by a pair ofholding devices, each comprising an upper and a lower holding pawl, andsuch holding devices are swung along arcuate paths having the respectivecenter located in proximity of the vertex of the adjacent V-shaped gap,so that both side portions of the starting and terminating ends of thebelt-shaped member are drawn toward each other until they abut againsteach other.

Thereafter, because the abutted end portions can be pushed towards thesurface of the drum to be joined to each other, the starting andterminating ends of the belt-shaped member, such as a tire tread, can beautomatically and accurately joined.

We claim:
 1. In an apparatus for joining together the two opposite ends of an elongated, belt-forming member during a belt-forming operation, each end of said belt-forming member comprising a center portion interposed between two side portions, the belt-forminq operation includingthe belt-forming member being wound on the peripheral cylindrical surface of a drum which is rotatable about an axis, and the center portions of the opposite ends of the belt-forming member being abutted against each other with a pair of opposite, substantially V-shaped side gaps being formed between the side portions of the opposite ends of the belt-forming member, the V-shaped side gaps each having a respective vertex adjacent to the abutting center portions of the two ends of the belt-forming member; the improvement comprising:a pair of movable rests positioned with respect to the drum and adapted so as to be movable along both a radial direction and an axial direction with respect to the drum, arms connected to said movable rests, said arms being positioned with respect to the drum and adapted so as to be swingable about respective arm axes radially extending with respect to the axis of the drum, the movable rests being positionable such that the arm axes pass through respective points located substantially between the side portions of the opposite ends of the belt-forming member, holding devices connected to said arms for holding the side portions of at least one end of said belt-forming member, and actuators connected to said arms which drive said arms arcuately about said respective arm axes to draw toward each other the side portions of the opposite ends of the belt-forming member.
 2. The apparatus of claim 1 wherein said rests are positionable such that said respective points are located substantially in the proximity of the vertices of the corresponding V-shaped gaps.
 3. The apparatus according to claim 1, wherein said holding devices each comprise a lower holding pawl attached to a lower end of the respective arm and an upper holding pawl facing the respective lower holding pawl and adapted to be moved with respect to the respective lower holding pawl substantially along a radial direction with respect to the axis of the drum.
 4. The apparatus according to claim 3, further comprising pushing device for pushing the side portions of the opposite ends of the belt-forming member toward the surface of the drum when the side portions of the opposite ends of the belt-forming member are in abutment with each other. 